Antioxidant or age resister



Patented Dec. 16, 1930 (Inrr o-fisrAres PATENT OFFICE ALBERT M. CLIFFORD, or AKRON, onio, ASSIGNOR ro THE GOODYEAR TIRE & RUBBER COMPANY, or AKRON, OHIO, A CORPORATION or OHIO Y ANTIOXIDANT on AGE, RESISTER awaiting. Origin-a1 ap licationfiled February 7,1928, Serial No. 252,677.

. i v filed Februaryj, 1929. Serial No. 337,736.

A 'My invention relates'to the treatment of rubbenandithas; particular relation toa method of enhancing theaging properties of that substance. 1 i

'6 This application is a division of application Serial No.252,67 7, filed February 7 1928.

More specifically my invention has for its object the provision of a material'which, when incorporated into .rubber, acts as an anti- 10 oxidant or age-resistor. jAnother object of the invention consists in'the provision of a material of the above des1gnated class that is composed of an aro niatic n1trosam1ne.

V 1 -=Heretofo re,'it has'been observed that certainamino bodies," when incorporated into rubber compounds, inhibit the oxidation and aging of those materials. 7

This invention consists in the discovery '20 that aromatic nitrosamine materials may also be employed as antioxidants or age-resisters. These materials may be introduced'into the rubber prior to vulcanization without materially acceleratingthe rate of vulcanization 'when the rubber compound is subjectedto heat. 1 The compoundsftherefore, do not disturlothe so-called balance of the rubber compound. They, therefore, may be introduced into standard formulae without changing the proportions of accelerators previously employed in the formulae.

Phenyl-beta-naphthyl nitrosamine specific example of a material which 'within the scope of the invention.

is a falls One method bywhich this material may be prepared is as follows:

Dissolve one part of phenyl-beta-naphthylamine in four parts of glacial acetic acid and twelve parts of alcohol. This solution should be chilled quickly in an ice bath and 3.25 parts of sodium nitrite, dissolved in a minimum amount of water, should be added thereto. Phenyl-beta-naphthyl nitrosamine and at other times as an oil which crystallizes after standing. The solid material may be filtered oil? and purified by recrystallizing it from alcohol or benzene. The purified product consists of a crystalline material having a yellowish color and having a melting point of separates out sometimes as a solid material,

Divided and this application 97 to 98 C. The crystalline character of the product, together with the definite melting pomtthereofl is clearly indicative that a true chemical reaction takes place when phenyl-betaenaphthylamine and sodium nitrite are brought together under the conditions described above.

Phenyl-beta-naphthyl nitrosamine may, of course, be employed as an antioxidantor ageresister in various rubber compounds. The following is an example of a compound which insures a product having excellent aging propertiesf Parts Extracted rubber 100 Zinc.oxide 5 Sulphur 3 Stearic acid 1.5 Hexamethylene tetramine 2 Antioxidant l Samples of material prepared in accordance with the preceding formula were vulcanize'd'by subjecting them to steam heat at 40 pounds pressure for periods of 30, and 70 minutes, respectively. One set of these samples was subjected to physical tests in order to ascertain their elasticity and tensile strength prior to aging. The results ofthese tests are indicated in the following table:

' a Time of Load in kgs/cm at cure Tensile Percent Mins; at strength elong. 500% 700% '40 ii p along. elong.

. A'second set of sampleswas subjected to artificial aging in an oxygen bomb heated to a temperature of 50 C. and to a pressure of 50 pounds per square inch for aperiod of six days. These samples were weighed both before and after artificial aging in. order to ascertain the per cent absorption of oxygen during the test. The samples were also subjected to physical tests similar to those con ducted upon the unaged samples. There- Sults of these tests are indicated in the@:fo1- ing table: V 1 p v 1 Load in kgs/cm at 5 Time of cnre Tensile Percent gigg ing Linn. v strength along-l 500% H 700% increase elong. I 'elong.

It Will be observed thatthe presence of the antioxidant inhibits the absorption of oxygento a very material degree, even when the samples are exposed to prolonged1heat,' 'ing in the bomb. The antioxidant also pre- "serves, to a material'extent, the original'elas naphthyl Vnitrosamine. Examples of such Berichte-20-2622 or j methods are disclosed in Annalen 243-300. 1 w

Although I'have described in detail only one embodiment of the invention, it Will be apparentto those skilled inthe artthat it is not solimited but that various minor modifications may be made therein Without de;

parting-from; the spirit ofthe invention or from the scope'of the appendedfclaims,

-What I claim is: v-

V 1. A method of preserving rubber Which comprises incorporating therein a material having the following structural formula i in which R and R are naphthyl groups. A V

2. A rubber product that has been vulcanized in the the formula RNR1,

N=O r in Which R and R are naphthyl groups.

3. A method ofpreserving rubber which comprises incorporating therein a dinaphthyl nitrosamine.'r a a 4:! A rubber product that has been vull oanized' in the trosamine. p v I 5. A method of preservingrubber which comprises vulcanizing it in the presence of a dinaphthyl' nitrosamine in which *both presence of a dinaphthyl vninaphthyl groups are similar;

ing the formula 6. A rubber product that has been vulcan- -'ized in thepresencejof a dinaphthylnitrosamine in which both'naphthyl groups are similar.

7. A method of'p'reservingrubberj which dinaphthyl nitros amine.

'comprisesincorporatingtherein a'betarbeta- 8, A rubber product that has been vulcanrizedin the presence of beta-beta-dinaphthyl fnitros amine; t .7 v

' -9. A method of preserving rubber Which V comprises 'vulcanizing it in the presence of a material selectedfrom a group comprising beta-beta-dinaphthyl hams amine] and; alpha-beta dinaphthyl nitros amine.

rubberproduct that hasbeen vul- $9 7 canizedintlie presence of a material selected from a group comprising beta beta-dinaphthyl naphthyl nitrosamine nitros amine and -al phaf-beta-di- 11. A rubber product that "has been vuli585 canized in'the presence of a compound hav- 7 where R is a beta naphthylene group and Bi is a material selectedifrom a group compris- 7 ing a and ,8 naphthylene. 1 V t 12: An accelerator composition comprisnitroso amine. T 1 I 13. An accelerator composition comprising an: organic accelerator and di-beta- I naphthyl nitroso amine. a 7 7 In witness Wl18I 6Of,I have hereunto signed my, name.

Signed at Akron,

and State of Ohio, U; S. A. this 4th day of Februar'yy l929. p

ALBERT M. CLIFFORD.

presence of a material havingin the county of Summit ing an organic accelerator and a di-naphthyl 

